Building construction



J1me 1933. c. w. DUNCAN 1,914,??9

BUILDING CONSTRUCTION Filed Oct. '7, 1929 Fig. l,

A TTORNEY.

Patented June 20, 1933 PATENT OFFICE CHARLES W. DUNCAN, OF SAUSALIT'O, CALIFORNIA BUILDING CONSTRUCTION T with concrete; that hollow tiles have been erected and subsequently filled with concrete, and that cellular blocks have been built into walls.

But so far as I am aware I am the first to build two interspaced walls of cellular blocks, held in spaced relation by invisible bridge clips, with oblique reinforcing rods arranged in said space prior to casting a monolithic wall within said composite wall, as

will be hereinafter more fully described.

Among the objects of the invention is to economically provide arigid, reinforced concrete, monolithic wall, cast in place without the use of removable molds.

Another object is to provide such a wall wherein transverse capillary attraction for moisture is absent.

A further object is to provide such a wall with the maximum of thermal insulation with the minimum of cross section. Other objects and advantages will appear as this description progresses. I

In this specification and the accompanying drawing the invention will be disclosed in its preferred form. .But it is to be understood that it is not limited to that form, because it may be embodied in other forms. It is also to beunderstood that in and by the claims following the description it is desired to cover the invention in whatsoever form it may be embodied.

In the one sheet of drawing:

Figure 1 is a fragmentary front elevation of a wall constructed in accordance with this invention, and showing an edge view of the side wall.

Figure 2 is a planview from above of the same.

Figure 3 is a detail in elevation of the '7 Application. filed October 7, 1929. Serial N0. 397,852.

assembling clip for interspacing and tying the surface blocks together.

Figure 4 is a top view of the same.

In detail the construction illustrated in the drawing comprises blocks or slabs of cellular plastic or cement. These slabs are cast in molds of the desired size. A very convenient size slab for small residences or bungalows is 8 X 16 inches and two inches thick. CO I These slabs are preferably formed of oubble stone. This is composed of ordinary Portland cement or other suitable cementitious plastic to which has been added a suitable chemical that will cause elfervesc-ence or bubbling prior to the'first setting reaction. The resultant mass is an aerated structure, resembling pumice. It has high. thermal insulating qualities, low specific gravity and the necessary strength for the purpose. This strength can be increased by reducing the effervescent reaction to increase the specific gravity of the resultant slab.

It can be sawed, chipped and hewn where fitting is necessary, and can be nailed into without splitting or fracturing. It forms a perfect key surface for the application of any form of plaster, stucco, paint, and the conventional interior and exterior finishes or tint may be added to the batch mix for natural finish.

It is as fire resisting as the material of which it is composed, and has a strong chemical and mechanical allinity for Port land cement, which latter advantage will be described later. Its bubble or cellular texture renders it practically impervious to moisture; that is, ordinary surface moisture will not penetrate through it as is the case of an equal cross section of brick, cement, and similar solid capillary structures.

These slabs can be very economically formed by casting a batch in a large shal low mold and cutting the mass into slabs of the desired dimensions with ablade while it is still plastic and before it sets hard. Greater accuracy, where this is a consideration, is gained by casting each slab in a snap mold for the preliminary set, before exposed curing. I

In building a wall, in accordance with this invention, it is desirable to have the top of the foundation 2, level and flat. Two parallel rows of slabs on edge are stood upright on the top of the foundation to form the first course. These are held firmly in spaced relation by the assembling clips.

A very effective form of clip is shown'in Figure 3. It comprisesthe cross bar 4, of the proper length, having the transverse spacers 5 and dowels 6 welded thereto The spacers are uniformly set apart a distance equal to the distance between the opposed faces of the slabs. The dowels are set apart a distance equal to the distance between the centers of the thicknesses of the slabs. These clips are composed of ordinary steel wire about one eighth of an inch in diameter.

Resistance to penetration is so low in the slabs that the dowels can be pushed into the slabs up to the cross bar l by hand. In the harder slabs they can be hammered in.

The succeeding courses of slabs are set against the upstanding spacers 55 and pushed down until the dowels 6 penetrate them and they rest upon the lower course.

This operation is repeated until the desired wall height is reached. This height is partly determinedby the space between the slabs. Consideration must be given to the fluidity of the concrete to be poured between the interspaced inner and outer slabs 1, 1.

In placing the slabs they are laid in break joint relation and interlocked at the corners,

inaccordance with the practice of bricklaying and masonry. This double or composite wall has suflicient lateral stability aidedby the cross clips to maintain itself when built into architectural structures.

The reinforcing bars 7 are introduced be tween the slabs 1, l at intervals. The short lengths at the corners are placed asfilhe wall is built up. The longer lengths can be placed after the wall has reached the desired height. These bars are preferably arranged in crisscross oblique formation to give better bracing effect.

One advantage of the wire form of clip is that it presents no obstruction to the entrance of the bars 7 which are guided by and supported by the clips that they. contact. These rods should be concentrated atthe center of the space. v

Suitable door and window casings are introduced into the wall as it is laid, in accordance with conventional practice. Thus as sembled, it is ready to pour.

The pouring consists of. introducing fluid concrete into the space between the slabs'l, 1, in the conventional manner.

Since it is desirable to produce a wall as thin as practicable, the concrete core 8 should be a rich mixture, sufficiently wet to flow freely and form a dense core.

The walls 1, 1 form a perfect form into which to cast the concrete core 8. The cellulated surface of the slabs causes the concrete to weld and key itself firmly thereto and transform the composite wall into a homogeneous reinforced monolithic whole.

The cellulated surfaces between the superimposed slabs prevent even thin grout from flowing out betweenthe slabs; neither do the slabs absorb or suck the water from the grout.

"The result is 'a perfect curing chamber for the concrete core 8, protected from extremes of heat or cold and too rapid evaporation.

The joists 9 of succeeding floors canbe laid atop the innerslabs 1, with their ends overhanging the space adjacent the outer slabs 1, so that the pouring of the core 8 will enclose the ends of the oists and firmly embed them therein. The inner slabs 1 are formed or trimmed to fit snugly between the joists. For concrete floors, the reinforcement bars thereof can be similarly anchored in the core 8.

Ordinary skilled labor can be used in the practice of this invention. Inequalities in the walls can be hewn away or rubbed even with the plane with a coarse stone. The slabs are a perfect key base for the application of plaster or any other desired plastic treatment or paint washes.

Such walls are cheap, strong, non-conducting to temperature, sound and moisture, and proof against earthquake, with other incidental advantages.

For buildings of several stories the cross section of the core can be increased and the strength of the slabs raised by reducing the effervescent medium and increasing the density proportionate to the load stress upon the walls of the lower stories and foundations.

Having thus described this invention what is claimed and desired to be secured by Letters Patent is:

l. A building structure comprising inner and outer interspaced walls of non-capillary aerated cementitious material, and a cementitious filler cast between said walls to form a substantially homogeneous monolithic Whole.

2. A buildin structure comprising inner and outer interspaced walls, composed of superimposed courses of non-capillary aerated cem'entilious slabs; cross clips consisting of horizontal cross bars and vertical dowels joining said walls; diagonally disposed reinforcing bars resting on said cross clips in the space between said walls; and a cementitious filler cast between said walls and adapted to adhere to the surfaces of said slabs to form a substantially homogeneous monolithic whole. 3 r

In testimony whereof I have'hereunto set my hand this 1st dayfof October A. D. 1929.

CHARLES w. DUNCAN. 

